<!DOCTYPE html>
<html>
	<body>
		<style>
:root { --not-a-color: 20px; }
p { background-color: red; }
p { background-color: var(--not-a-color); }
		</style>
		<!-- this should have 'red' because var() has invalid value for color -->
		<!-- TODO: not really supported by NEL currently -->
		<div data-ruleset="background-color: red;" />
	</body>
</html>
